Manufacture of paste rosin size in closed circuit reactor



June 25, 1968 J, c. 0| PLACIDO 3,39

MANUFACTURE OF PASTE ROSIN SIZE IN CLOSED CIRCUIT REACTOR Filed Sept. 1,1965 INVENTOR. JOH/V CARL DiPLAC/DO A TTOR/VEY United States Patent3,390,004 MANUFACTURE 0F PASTE ROSIN SIZE IN CLOSED CIRCUIT REACTOR JohnCarl Di Placido, Mobile, Ala., assignor to American Cyanamid Company,Stamford, Conn., a corporation of Maine Filed Sept. 1, 1965, Ser. No.484,263 2 Claims. (Cl. 106238) ABSTRACT OF THE DISCLOSURE Paste rosinsize is manufactured by introducing hot paste rosin size, hot aqueousalkali metal alkali solution, and molten rosin in appropriateproportions into the vortex of a centrifugal pump rotating sufficientlyrapidly to emulsify the rosin.

The present invention relates to an improvement in the saponification ofrosin with aqueous alkali metal solution to form paste rosin size.

Paste rosin size (rosin saponified with aqueous sodium hydroxide orother aqueous alkali metal solution to a solids content of about 60%80%solids by weight and a free rosin acid content of about 5% to 25%) canbe cheaply and simply prepared by the continuous process disclosed inAnderson et al. US. Patent No. 2,842,453. According to this patent,molten rosin and hot aqueous alkali metal alkali solutions are piped inpaste rosin sizemaking proportions (along with hot paste rosin size) toa centrifugal pump in which the rosin is emulsified, with conversion ofthe rosin to paste rosin size state. (In commercial practice, thecomponents are metered separately and automatically and are introducedunder pressure into the closed circuit of the reactor.) The rosin israpidly emulsified by the whirling action of the pump (the paste rosinsize acting as emulsifying agent) and reacts with the alkali metalalkali, forming paste rosin size.

While this method has greatly simplified the manufacture of paste rosinsize, in large-scale operation, it has been diflicult to supply themolten rosin and alkali metal alkali solution into the centrifugal pumpat a uniform continuous rate without use of high injection pressures.When these components are introduced at moderate pressure into thepiping, severe oscillations occur in the rate at which the rosin andalkali metal alkali solutions are metered with corresponding variationsin the quality of the size which is discharged from the pump. The causeof these variations has not been ascertained, but is probably thetendency of the rosin to travel as slugs rather than as a uniformlydistributed component of the reaction mixture. It became desirable,therefore, to overcome these difficulties without use of specialauxiliary equipment or specially responsive controls.

The discovery has nOW been made that the aforementioned ditficulties areobviated in the process described when the alkali metal alkali solutionand rosin are introduced directly into the vortex which is present atthe inlet side of the centrifugal pump when the pump is working atemulsification speed. I have found that as a result, the two materialspass smoothly and uniformly into and through the pump from their time ofintroduction, and undergo much more uniform reaction than has heretoforebeen the case. Emulsification of the rosin to paste rosin sizeconsequently takes place almost instantly and uniformly, typicallywithin about second, with production of a better and more uniform gradeof paste rosin size than heretofore produced.

At the present time, paste rosin size may contain minor amounts ofsodium chloride, potassium chloride or a lower alkanol as fiuidifyingagents, and pentachloro- 3,390,004 Patented June 25, 1968 phenol as amold growth inhibitor. These and other special additives such as arecustomarily present in rosin size may be introduced separately into thecentrifugal pump or, if preferred, they may be metered into the alkalimetal alkali solution, the molten rosin, or the paste rosin size productas appropriate in each instance.

The invention is further illustrated by the drawing wherein:

FIGURE 1 is a schematic elevation of an electric motor-drivencentrifugal pump provided with supplementary inlet pipes which permitthe pump to be used for the practice of the present invention;

FIGURE 2 is an enlarged view of the inlet cover and upstream half of thecollar of the feed side of the pump, showing the arrangement and lengthof the feed pipes therein;

FIGURE 3 is a view into the component of FIGURE 2 presenting a differentvieW of the arrangement of the inlet pipes; and

FIGURE 4 is a view into the centrifugal pump from the feed side with theinlet cover and collar removed, showing the impeller vanes of the pump,the area typically occupied by the eye of the vortex, and the area overwhich the feeds are introduced into the pump.

In the drawings, the same numbers are used to identify the same parts.

In FIGURE 1, 1 represents a centrifugal pump supported on bearing casing2 driven by variable speed electric motor 3 and having an inlet collar4. To this collar (which contains the vortex when the pump is in normaloperation) is affixed flanged conical inlet cover 5a having axial supplyorifice 5b, alkali metal alkali supply pipe 6, and molten rosin supplypipe '7. The pump has tangential exit orifice 8. The pump collar andcover are of conventional design except for pipes 6 and 7, which arepresent to permit practice of the present invention.

In FIGURE 2, the alkali metal alkali supply pipe 6 is shown as extendingaxially beyond the flange of cover 5:: by a distance sufiicient tointroduce the solution into the eye of the vortex which forms in collar4 when the pump is in operation. Rosin supply pipe 7 terminates in anadja cent location 50 as to ensure most rapid contact between the rosinand the alkali metal alkali soiution.

In FIGURE 4, the inlet area is shown as extending over the entire inletface of the pump (the area ringed by collar 4- as indicated by S and iscoextensive with the area swept by impeller vanes 10. The periphery of atypical vortex is indicated by dotted circle 11.

In operation, paste rosin size having a temperature above the meltingpoint of rosin is admitted under pressure through axial pipe 5b intoinlet cover 5a which distributes paste rosin size as emulsifying mediumuniformly over inlet face 9 of the pump. The pump is operated at leastsufficiently fast to emulsify the rosin.

Hot alkali metal alkali solution and molten rosin are respectivelyadmitted under pressure from automatic meters (not shown) through pipes6 and 7 in proportions suitable for formation of paste rosin size.

Best emulsification and reaction of the rosin has generally occurredwhen the ratio of the volume of the paste rosin size which is admittedas emulsifying agent to the combined volumes of the molten rosin andalkali metal alkali solution is between 3 :1 and 5:1.

The present invention is usefully employed in the process of saidAnderson et al. patent, wherein a closed circuit reactor is employed,and the rosin and alkali metal alkali solution are emulsified inrecirculated paste rosin size.

The invention need not be practiced in the specific form of apparatusshown in the drawing. Thus, for example, the pipe for admitting therosin to the vortex in the pump need not be adjacent to the pipe usedfor admitting the alkali metal alkali solution but may be concentrictherewith.

I claim:

1. In the continuous manufacture of paste rosin size by a processwherein molten rosin and aqueous alkali metal alkali solution in pastesize making proportions and paste rosin size as emulsifying medium forsaid rosin are piped to a centrifugal pump rotating at sutficient speedto form a vortex on its intake side and to emulsify said rosin, theimprovement which consists in introducing said alkali metal alkalisolution and said rosin into said vortex, whereby said alkali metalalkali solution and said rosin References Cited UNITED STATES PATENTS7/1951 Russell 25996 7/1958 Anderson et al l06238 ALLAN LIEBERMAN,Primary Examiner.

